Hi, the above is usually caused by a driver trying access memory and something goes wrong. The driver in this case looks like it's Smb_driver_Intel.sys which relates to the touchpad. BiosVendor = LENOVO BiosVersion = 6BCN40WW (V2.00) BiosReleaseDate = 01/24/2013 Laptop drivers are supplied by the machines manufacturer and looking through the support section I noticed that there are updates for the Bios too. If you apply this update please double check that the support page is correct for your model, your support page is here: .Y400 Laptop (IdeaPad)http://support.lenovo.com/gb/en/products/laptops-and-netbooks/ideapad-y-series-laptops/ideapad-y400-notebook/?tabName=Downloads

AVG is known at times to cause the odd issue, YAC I had to do some Googling to find out anything about it and also at times causes issues. I'm not sure whether having both installed together could be causing problems but if the bsod continues you at least have another avenue to pursue if updating the drivers/Bios doesn't help.

A really good combination known not to conflict and is used by many of us here is the combination of Windows Defender along with Malwarebytes. I've personally used this method for as long as it's been around and I've never had an issue (touch wood ).https://www.malwarebytes.org/

Ok so apply the driver updates and Bios (please go through everything ). If the bsod continues then think about your security and what I've suggested.

Hi, same again I'm afraid. I can see in the call stack (a list of sub routines prior to the bsod) that it's the Touchpad driver being tripped but what is actually tripping it remains to be seen. I did notice this in your system: appobserver64.sys Thu Oct 09 19:10:47 2014: Nielson Online an app known to cause issues. Please remove to test.

Hi, same again. If you look on the driver support page and then look under drivers for Windows 8.1 you'll see that there is a driver dated 2013. Is this the driver you tried or the Windows 8 2012 version?

Also have you been through the driver support page with a fine toothcomb and updated everything to do with your system? I'm sure I can see updates for GPU drivers and wonder if any others have been missed?